MECHANISMS IN ENDOCRINOLOGY: Metabolic and inflammatory pathways on the pathogenesis of type 2 diabetes

Maternal and paternal family history of diabetes in second-degree relatives and metabolic outcomes at age 5-6 years: The ABCD Study

AIM

To investigate whether children with a family history of diabetes (FHD) in second-degree relatives (grandparents, aunts/uncles) are at increased risk of developing obesity and diabetes, and whether the risk differs between maternal or paternal transmission.

METHODS

In the multiethnic population-based cohort Amsterdam-Born Children and Their Development (ABCD) Study, body mass index (BMI), waist-to-height ratio (WHR), fat percentage (fat%), fasting glucose and C-peptide in 5- or 6-year-old children with no second-degree FHD (n=2226) were compared with children with maternal-only (n=353), paternal-only (n=281) or both maternal and paternal (n=164) second-degree FHD. Children of diabetic mothers or fathers were excluded.

RESULTS

None of the children in any of our FHD categories differed in body composition after adjusting for maternal, paternal and childhood lifestyle covariates. However, children with both maternal and paternal second-degree FHD had increased C-peptide levels (0.03nmol, 95% CI: 0.01-0.05) compared with those in the other three study groups. Results were similar when analyses were restricted to only the Dutch children.

CONCLUSION

Children with FHD in second-degree relatives on both maternal and paternal sides already have higher C-peptide levels at an early age. This might be the result of a double burden of a shared obesogenic lifestyle, or of more diverse diabetogenic genes compared to children without FHD or with only FHD in one side of the family. In any case, second-degree FHD could be used as a public-health screening tool to identify children at risk of adverse metabolic outcomes and of possible future disease.

Multiplex Biomarker Approaches in Type 2 Diabetes Mellitus Research

Type 2 diabetes mellitus is a multifactorial condition resulting in high fasting blood glucose levels. Although its diagnosis is straightforward, there is not one set of biomarkers or drug targets that can be used for classification or personalized treatment of individuals who suffer from this condition. Instead, the application of multiplex methods incorporating a systems biology approach is essential in order to increase our understanding of this disease. This chapter reviews the state of the art in biomarker studies of human type 2 diabetes from a proteomic and metabolomic perspective. Our main focus was on biomarkers for disease prediction as these could lead to early intervention strategies for the best possible patient outcomes.

[Bone and adipose tissue formation]

Leptin has been described to have a crucial role in bone homeostasis by systemic as well as local action. Systemically, leptin seems to inhibit bone formation controlled by a feedback loop including osteocalcin and insulin. Even though the action seems to be bone site specific, as well as gender- and time-dependent, the results showing the interaction of these three factors are in part still inconsistent. In this article the complex effects of leptin, insulin, and osteocalcin on bone and fat metabolism are summarized.

At the interface of antioxidant signalling and cellular function: Key polyphenol effects

The hypothesis that dietary (poly)phenols promote well‐being by improving chronic disease‐risk biomarkers, such as endothelial dysfunction, chronic inflammation and plasma uric acid, is the subject of intense current research, involving human interventions studies, animal models and in vitro mechanistic work. The original claim that benefits were due to the direct antioxidant properties of (poly)phenols has been mostly superseded by detailed mechanistic studies on specific molecular targets. Nevertheless, many proposed mechanisms in vivo and in vitro are due to modulation of oxidative processes, often involving binding to specific proteins and effects on cell signalling. We review the molecular mechanisms for 3 actions of (poly)phenols on oxidative processes where there is evidence in vivo from human intervention or animal studies. (1) Effects of (poly) phenols on pathways of chronic inflammation leading to prevention of some of the damaging effects associated with the metabolic syndrome. (2) Interaction of (poly)phenols with endothelial cells and smooth muscle cells, leading to effects on blood pressure and endothelial dysfunction, and consequent reduction in cardiovascular disease risk. (3) The inhibition of xanthine oxidoreductase leading to modulation of intracellular superoxide and plasma uric acid, a risk factor for developing type 2 diabetes.